By way of example, DE 197 39 395 A1 discloses a broadcast radio receivers, for installation in motor vehicles. This receiver has a receiving section with at least one connection, via which further components can be connected. An antenna in the form of a rod can be plugged in above the receiving section.
An antenna for automobiles is also disclosed, for example, in DE 298 21 723 U1. The antenna has an antenna foot which comprises a protective cover in the form of a housing or shroud, and a baseplate which can be mounted on the roof of the automobile. Various electrical devices are accommodated in the internal space between the shroud and the baseplate. A line 12 leads to the actual antenna element devices, which project outward from the foot part. What is referred to as a combination antenna element is used for this purpose, which is provided at its lower end with a threaded projection, in order to make it possible then to screw the threaded antenna element into and out of a threaded bushing in the foot part.
In this case, further devices can also be accommodated in the antenna foot, in order in the end to make it possible to receive different frequency bands via one or more radio-frequency lines. Specifically, antennas such as these should be suitable, for example, for various networks in the mobile radio band (for example the D network or E network, as well as for the UMTS frequency band from about 1 900 MHz to 2 170 MHz). Furthermore, if required, it should also be possible to receive and process GPS signals and/or to receive VHF broadcasts or programs.
The antennas available on the market at the moment have been proven in principle, although different implementation and conversion principles are known.
However, against the background of the last-mentioned antenna of this generic type, there is a problem, in that an antenna such as this with what is referred to as a combination antenna element is now also intended to be suitable for the UMTS Standard in addition to the normal mobile radio band in the DoCoMo band, in the AMPS band, and/or in the GSM 900 band i.e., in the 810 to 960 MHz band) and/or in the GSM 1 800 and/or in the GSM 1 900 band (i.e., in the 1 710 and 1 990 MHz band). This is because an antenna which is suitable for this overall range implies that, for the higher frequencies which can be transmitted, the antenna elements which are provided for this high frequency range must be designed to be smaller, that is to say shorter, and this also applies to the antenna bracket However, this would then lead to the antenna having to be modified overall, including the existing antenna element. However, this is contrary to what is referred to as the “identical parts” concept, on the basis of which, for example, one antenna element type should be used for different purposes.
A two-band antenna has been disclosed, for example, in the B1 version of U.S. Pat. No. 6,191,747. This is a multiband antenna using coils for phase shifting in order to form a monopole gain antenna element.
A two-band motor vehicle antenna which forms this generic type and has an antenna foot has been disclosed in WO 0 171 847 A1, in which a connecting line is connected to the antenna element arrangement via an intermediate line piece.
Against the background of the prior art of this generic type, the object of the exemplary illustrative non-limiting technology herein is therefore to provide an improved multiband antenna arrangement.
The technology herein provides an intrinsically highly proven motor vehicle antenna that can now also be used, for example, for the UMTS Standard or other considerably higher frequency band, and without any reduction to the physical height or physical size. In an exemplary illustrative implementation, this is possible because the electrical line which leads to an antenna element for the higher frequency range or a bracket which leads to the antenna element for the higher frequency range is provided with an extension. The extension can be implemented in such a way that the supply lines are lengthened beyond a connecting point or contact point via which the antenna element makes electrical contact with the supply line, and preferably ends freely. If the electrical supply line is formed by an electrically conductive bracket, then the bracket can be lengthened beyond the contact-making point with the first antenna element, with the contact-making point in this case at the same time being used as a connecting point or even as an attachment point for the antenna element. However, the extension need not necessarily be provided such that it runs continuously over the electrical wire or bracket, but may also be in the form of a line section that is passed back. It is also possible to use an extension which points downward via the connecting point between the electrical supply line or bracket and the electrical antenna element which is provided for the higher frequency range, and which possibly ends shortly before the motor vehicle roof.
Extensions which, for example, are in the form of a disk or of a plate are also suitable, and preferably are provided at the connecting point between the electrical supply line or bracket and the antenna element which is provided for the higher frequency range.
However, normally, not only is one antenna element used, preferably in the form of a bolt, which is provided for the higher frequency range, but a coil followed by a further antenna element is then used in the extension of this antenna element.
In the process, it should be remembered that the entire antenna element arrangement including the antenna bracket acts as an antenna element for the low frequency ranges, that is to say for long waves, medium waves, short waves and the VHF band. For the DoCoMo, the AMPS and the GSM 900 bands (which corresponds to 810 to 960 MHz), the antenna bracket and the lower part of the actual antenna clement arrangement, that is to say generally of the antenna clement bolt which is provided for his purpose, still act together with one part of the coil that has been mentioned as antenna elements. However, if the frequency is raised further, that is to say for example to the GSM 1 800 and GSM 1 900 bands (which correspond to 1 710 MHz to 1 990 MHz), only the antenna bracket and the lower antenna bolt then still act as antenna elements. However, only the antenna bracket and its extension then still act as antenna elements in the UMTS band (1 900 to 2 170 MHz).